how do I download & install synergy 1.8.8 on linux

Computer 1 updated to 1.8.8 but computer 2 is showing me 1.6?? and if they don't match they don't work.
the synaptic package manner is showing me the old one on computer 2?? How do I get it to catch up?

Sorry, my fault. The command should have been
apt-cache policy synergy

But the cause of your problem is already visible:
One of your computers is running Ubuntu 16.04 which has synergy 1.6.2, and the other computer is running Ubuntu 18.04 with synergy 1.8.8
see https://launchpad.net/ubuntu/+source/synergy

If you want to have the same version of synergy on two computers, then you should care for identical Ubuntu releases on these systems.
Everything else (like installing synergy 1.8.8. on Ubuntu 16.04) needs additional manual actions outside the Ubuntu standards.

OK I've download a 1.8.8 stable and extra it. it's in my download file. opened it click on install that did nothing. on the read me it says.
Just use "hm conf" and "hm build" to compile
I don't know what to do with that.